2023_programme: Diversity in the ocean noise trends observed from different CTBTO hydroacoustic stations

• Session: 03. Comprehensive Nuclear-Test-Ban Treaty Monitoring and its Civil and Scientific Applications
  Organiser(s): Georgios Haralabus, Mario Zampolli and Peter Nielsen
• Lecture: Diversity in the ocean noise trends observed from different CTBTO hydroacoustic stations [invited]
  Paper ID: 2079
  Author(s): Cheong Sei-Him, Wang Lian, Robinson Stephen, Harris Peter, Livina Valerie
  Presenter: TBA
  Abstract: This paper describes the results of determining the long term and seasonal trends in ocean sound from deep-ocean hydrophone stations operated by the CTBTO (with data spanning periods of up to 19 years). The analysis method uses Gaussian Process regression, a machine learning method which provides a flexible way of modelling data to account for evolving seasonal and long-term trends, and also provides uncertainties in the predicted levels. The data were pre-processed using a 12 node High Performance Cluster to aggregate the results into statistical levels and to calculate associated coverage intervals. The analysis is applied to decidecade frequency bands in the range from 10 Hz to 100 Hz, and aggregated over different time intervals (days, weeks, months, years). \nThe analysis here focuses on the data from the Southern Ocean, Pacific Ocean, and Atlantic Ocean. The features of the data are described, including the differences in the seasonal variation and the long-term trends observed between stations. The discussion is informed by considerations of potential drivers for the trends, including changes in natural and anthropogenic sources of sound, and in ocean environmental conditions.\n
• Corresponding author: Mr Stephen Robinson
  Affiliation: National Physical Laboratory
  Country: United Kingdom
  e-mail: